I've got a lot of pictures, and it's much easier to just share an album than to embed everything here:
https://imgur.com/a/HU2mHYou'll see there's a mess of rubber bits in everything. I have not found any damage aside from the missing tooth on the governor gear. Aside from the rubber, the pump seems very clean. I of course don't know what I'm doing, but I haven't seen any indications of oxidation or pitted surfaces. I'm thinking I'll clean everything, take apart my 1.6 pump for the gear, and then reassemble using Vaseline.
I have two big questions: I've got a reseal kit and will replace all the seals and copper washers etc. I understand that a 'rebuild' is more involve, and should involve calibration and so on. I of course don't have access to the equipment needed for calibration. So, aside from cleaning and resealing, is there anything I should do while I've got this apart? I think the input shaft bushing is in good condition . . .
Second question: As I said above, I took this pump apart out of curiosity without the goal of attempting a repair. Once I saw, after removing the head, the damaged gear, and spring and rubber bits, I kept going just to see what else what damaged but not imagining I'd attempt a repair. Thus, I didn't document the process or mark anything, but I also didn't mess with anything that I knew needed to be replaced in some specific orientation -- however, I learned later that I overlooked something in this regard.
I have not touched any of the adjustment screws on the head, and I'm not worried about the throttle lever (I have dealt with this before and didn't have much trouble getting the position right). And it may still be marked from before. I know how to orient the cam-plate.
But doesn't the 'governor shaft' (or something) in the head of the pump need to be oriented a certain way (which I should have marked)? If so, how much of a concern is this and what can I do?
I did at least try to keep the parts together such that various wear surfaces (like on the rollers) would all be positioned as they were originally.
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As for cleaning, my plan is to maybe use an ultrasound machine, and at least blast everything with WD40 and then compressed air. It will be a lot of trouble to be sure I've cleaned out all of the rubber.
By the way, if anyone happens to have a replacement for this damaged gear, I would prefer to buy a replacement than to tear down my 1.6 pump, just because the latter was working and I hate to ruin working parts, even if they're not worth much, or of any use to me!